Radio Shack 120-2130A - Manual (Page 8)

or it might not be marked at all.
4. Connect the white FRONT LEFT (+) wire to the left speaker's positive
terminal.
5. Connect the green/black REAR LEFT (-) wire to the left speaker's
negative terminal.
Connecting the Antenna
Connect the vehicle's antenna cable to the stereo's large black antenna
connector.
Testing the Connections
Make sure you have securely made all other connections, then plug the
harness's connector into the stereo's 14-pin wiring socket.
Then reconnect the cable to the vehicle battery's negative terminal to
test the connections.
Turn on your vehicle's ignition. The display should light and the
currently set time (or 12:00) should appear on the display when you turn
the left inner shaft clockwise until you hear it click to turn on the
stereo.
CAUTION: If the stereo does not work, immediately disconnect the cable
from your vehicle battery's negative (-) terminal. Then recheck
your connections.
After you verify that the display lights and the clock appears, follow the
instructions in "Mounting the Stereo" below.
Mounting The Stereo
Be sure you test the stereo first and verify that it works properly. (See
"Making the Connections" above.) Then follow these steps to mount the
stereo.
1. Disconnect the cable from the vehicle battery's negative (-) terminal.
2. Disconnect the wire harness and the antenna.
Note: If you are using an in-dash installation kit, follow the
procedure outlined in the kit, and proceed to Step 4 (skip Step
3).